Assessment of land use effect, mapping of human health risks and chemometric analysis of potential toxic elements in topsoils of Aran-o-Bidgol, Iran.

This study examines topsoil contamination in Aran-o-Bidgol urban region of central Iran, with a focus on potentially toxic elements (PTEs). A total of 135 topsoil samples in different land types were characterized, ranging from areas with agricultural farms, desert, industrial and residential activity, and brick kilns. The average concentrations of Cd, Pb, Cu, Ni, Cr, Co, Fe, Zn, and Mn were 0.72, 11.41, 14.82, 29.87, 51.13, 106.69, 8741.87, 48.59, and 346.42 mg kg-1, respectively, which all exceed the local background levels. The results reveal that land use significantly affected PTE concentrations. Cr, Co, Mn, and Fe concentrations in soils of residential and brick kiln areas were especially high. In contrast, concentrations of Cu, Ni, and Zn were higher in agricultural and residential areas. Risk assessment analysis showed that the sum of toxic units for PTEs for brick kilns (1.72), residential (1.82), and agricultural (1.79) areas exceeded those of other land types and that Ni and Cr contributed the most to the high toxic risk index values. Both carcinogenic and non-carcinogenic risk indices of PTEs in soils were within an acceptable limit, except for the cancer risk of Ni (3.52E-04) and Cr (3.00E-04) among children. The spatial hazard index and carcinogenic health risk of PTEs showed that samples from the southwestern parts of the study area might pose significant health problems to adults and children. This study demonstrates how combining different techniques can help spatially characterize PTE accumulation and protect populations at risk.

Hybrid approaches based on hydrodynamic cavitation, peroxymonosulfate and UVC irradiation for treatment of organic pollutants: fractal like kinetics, modeling and process optimization.

Hydrodynamic cavitation (HC) was emerged as one of the most potential technologies for industrial-scale wastewater or water treatment. In this work, a combined system of HC, peroxymonosulfate (PMS) and UVC irradiation (HC - PMS - UVC) was constructed for effective degradation of carbamazepine. The effect of several experimental parameters and conditions on the carbamazepine degradation was considered. The results show that the degradation and mineralization rates increases with an increase in the inlet pressure from 1.3 to 4.3 bars. The rates of carbamazepine degradation with the combined processes of HC - PMS - UVC, HC - PMS, HC - UVC, and UVC - PMS were 73%, 67%, 40% and 31%, respectively. Under the optimal conditions of reactor, the carbamazepine degradation and mineralization rates were 73% with 59%, respectively. The kinetics of carbamazepine degradation was studied applying a fractal-like approach. So, a new model was proposed by combining first order kinetics model and fractal-like concept. The obtained results show that the proposed fractal-like model gives a better performance compared with traditional first order kinetics model. It has been demonstrated that the HC - PMS - UVC process is a potential treatment method to destroy pharmaceutical pollutants from water and wastewater sources.

Abundance, characteristics, fate, and removal of microplastics during municipal wastewater treatment plant in the west of Iran: the case of Kermanshah city.

The threat of microplastics (MPs) in aquatic systems is almost a new challenge in environmental management. The municipal wastewater treatment plants (WWTPs) act both as collectors of MPs from anthropic use and as a source to natural environments. This study is aimed to determine the abundance, characteristics, and removal of MPs in a municipal WWTP with conventional activated sludge process. Particle size/type, influent loads, and removal rate of MPs in bar screen, grit chamber, primary sedimentation, returned activated sludge, and secondary clarification units of this WWTP were studied by collecting composite samples from wastewater and sludge over a 3-month sampling campaign. Suspected MP particles were counted by light microscopy and characterized using SEM, EDS, FTIR, and TGA-DSC techniques. The mean total MPs, fibers, and fragment concentration after the grit chamber were 6608, 3594, and 3014 which were reduced to 1855, 802, and 1053 particles/L in the effluent, respectively. The sludge retention of total MPs, fibers, and fragments were 8001, 3277, and 4719 particles/L, respectively. The overall efficiency of WWTP with an activated sludge process to remove MPs was 64% and it removed 66.6% and 60% of fibers and fragments, respectively. Fibers were the dominant shape for the collected samples after the grit chamber and fragments were prevalent in the effluent. Polyethylene polymer was detected in most wastewater samples. Existing treatment processes are effective in the removal of MP particles but still act as a potential source to the aquatic ecosystem.

Nicotine consumption rate through wastewater-based epidemiology: a systematic review, meta-analysis and probabilistic risk assessment.

Wastewater-based epidemiology (WBE), as a rapid tool, is used to measure and monitor illicit drug consumption in the population. This method is also used to bridge biomarkers of exposure, contaminants, and human health. Smoking cigarettes and tobacco use are everyday habits in nowadays community. This systematic review and meta-analysis aimed to calculate nicotine consumption globally. The related studies were retrieved within international databases including Scopus, Google Scholar, and Web of Science, up to February 2021. It included twenty-one articles containing 87 measurements covering 275.3 million people with total wastewater samples of 2250. Results showed that the highest and lowest nicotine consumption rate (mg/1000 inh./day) was in Portugal (5860) and Vietnam (1201), respectively. The global pooled nicotine consumption rate was 2476 mg/1000 inh./day (95% CI (2289-2663). Based on WBE results, the average daily cigarette smoked per smoker is 14 (95% CI: 10-18 cigarettes/inh./day), close to the value of 14.2 reported by the survey and interview studies. Risk assessment of the nicotine consumption rate through WBE was calculated by the margin of exposure (MOE) approach. In total, 82% of nicotine consumption measurements were located in the "risk" level (MOE < 100), and 18% of the MOE values were between 100-1000. The results reveal that nicotine consumption risks need immediate global and local action strategies. Finally, these findings are helpful for healthcare agencies and policy-makers to take action against tobacco use prevalence.

Microplastic abundance, distribution, and characterization in freshwater sediments in Iran: a case study in Kermanshah city.

This paper focuses on abundance, distribution, and characteristics of microplastics (MPs) in freshwater sediments of Sarab Niloofar Lake, Kermanshah, Iran. After selecting an appropriate method for extraction of MPs, the characterization such as polymer types, surface morphology, and trace elements has been determined using Fourier transform infrared spectroscopy, scanning electron microscopic, and energy-dispersive X-ray spectroscopic analysis, respectively. The results highlighted that all sampling locations were contaminated by MP abundance ranged from 1733.33 to 4400 items kg-1 d.w with an average of 2483.59 ± 805.30 items kg-1 d.w. MPs with a size range of 0.025 to 1 mm (25-1000 µm) were the most frequently detected MPs in size (62%). Furthermore, the MPs found in this area mainly contain fiber (61%), fragment (19%), film (9%), foam (6%), and pallet (5%). The main color for detected MPs in sampling stations was black (51%) and followed by white/transparent (27%), red (11%), blue (7%), and yellow (4%). The results of polymer identification revealed that the polyethylene, polystyrene, polyurethane, and polypropylene were the principal polymers. This research work emphasized that various types of MPs have been distributed in freshwater sediments of Sarab Niloofar Lake, which is a first useful data for MPs in one the most important Kermanshah's tourist area.

Fabrication of novel magnetic CuS/Fe3O4/GO nanocomposite for organic pollutant degradation under visible light irradiation.

The magnetic nanocomposites composed of copper sulphide, iron oxide, and graphene oxide (CuS/Fe3O4/GO) were synthesized through a facile sol-gel combined with hydrothermal techniques for photodegradation of methylene blue (MB) as a model organic pollutant. The as-prepared samples were characterized by powder X-ray diffraction (XRD), vibrating sample magnetometer (VSM), differential reflectance spectroscopy (DRS), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray analysis (EDX) and results confirmed successful synthesis of magnetic nanocomposite. Presence of Fe3O4 and GO in nanocomposite induced a synergistic effect in CuS performance as CS88F6G6 (i.e. 88% CuS, 6% Fe3O4, and 6% GO). The photocatalytic degradation efficiency of MB reached up to 90.3% after exposure to visible light irradiation for 80 min. The composite nanosheets are photostable, reusable, and magnetically recoverable, revealing potential application in removal of organic pollutants.

Highly efficient visible-driven reduction of Cr(VI) by a novel black TiO2 photocatalyst.

Finding a facile and practical method to produce black TiO2 remains a challenge. Bismuth-vanadium co-doped black TiO2 (BVBT) was synthesized as a visible light driven photocatalyst by a simple one-pot hydrothermal method. The synthesized BVBT was characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), UV-vis diffuse reflectance spectroscopy (UV-Vis DRS). The light absorption of the synthesized Bi-V co-coped black TiO2 nanoparticles was significantly improved in the visible and infrared regions. The XRD patterns indicated that the black TiO2 contained mixed phases of brookite, anatase, and rutile of TiO2. This was further confirmed by Raman spectroscopy. The photocatalytic activity of the sample was evaluated by reduction of hexavalent chromium (Cr(VI)) under visible light irradiation. Among investigated hole (h+) scavengers, ethylenediaminetetraacetic acid (EDTA) led to the highest reduction of Cr(VI) with a molar ratio of 1:5 (EDTA:Cr(VI)). The results indicated that the Bi-V co-coped black TiO2 nanocomposite can reduce 94% of 1 mg/L of Cr(VI) within 20 min irradiation time (pH 3 and catalyst dose of 1 g/L). Introducing a simple method to synthesize black TiO2 which has absorption in the visible and infrared region can open up new applications.

Estimating alcohol consumption by using wastewater-based epidemiology in Adana Province, Turkey.

Increased alcohol consumption, especially among young people, is a major concern in Turkey as it is around the world due to negative effects on public health and safety. Regarding this, it is pivotal to monitor and therefore control alcohol use in public. In this case, wastewater-based epidemiology (WBE), which is the in-depth analysis of wastewater and a relatively new method, can deliver complementary information concerning the abuse of different substances. The proven potential of the WBE approach offers new promises in the process of monitoring alcohol use, namely the monitoring of the levels of ethyl sulfate (EtS) as a urinary biomarker of alcohol consumption, and it is a powerful mean to estimate alcohol use at the community level. In this study, raw 24-h composite wastewater samples were collected from Seyhan and Yüregir wastewater treatment plants (WWTPs) in Adana Province for one week per season (October 2016-August 2017). The fast and validated analytical method was performed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) and therefore applied to the analysis of ethyl sulfate (EtS). Obtained concentration values were back-calculated, and regional and temporal social usage rates were determined. Higher values were calculated for both WWTPs on Sunday. Alcohol consumption in the region served by Seyhan WWTP was higher than Yüregir WWTP. The results showed that the levels of alcohol consumption during given periods in Adana ranged from 659.8 to 8998.7 mL/day/1000 per person with an average value of 4983.9 and 3924.2 mL/day/1000 inhabitant in Seyhan WWTP and Yüregir WWTP, respectively. This study shows that weekly and annual trends in alcohol consumption can be detected quickly from wastewater analysis.

A global systematic review and meta-analysis on illicit drug consumption rate through wastewater-based epidemiology.

Wastewater-based epidemiology (WBE) is a complementary, well-established comprehensive, cost-effective, and rapid technique for monitoring of illicit drugs used in a general population. This systematic review and meta-analysis is the first to estimate the rank and consumption rate of illicit drugs through WBE studies. In the current study, the related investigations regarding the illicit drug consumption rate based on WBE were searched among the international databases including Scopus, PubMed, Science direct, Google scholar, and local database, Magiran from 2012 up to May 2019. The illicit drug consumption rate with 95% confidence intervals was pooled between studies by using random effect model. The heterogeneity was determined using I2 statistics. Also, subgroup analyses were conducted to examine the possible effects of year and location of studies on observed heterogeneity. Meta-analysis of 37 articles indicates that the overall rank order of illicit drugs according to their pooled consumption rate can be summarized as tetrahydrocannabinol or cannabis (7417.9 mg/day/1000 people) > cocaine (655.7 mg/day/1000 people) > morphine (384.9 mg/day/1000 people) > methamphetamine (296.2 mg/day/1000 people) > codeine (222.7 mg/day/1000 people) > methadone (200.2 mg/day/1000 people) > 3,4-methylenedioxymethamphetamine (126.3 mg/day/1000 people) > amphetamine (118.2 mg/day/1000 people) > 2-ethylidene-1,5-dimethyl-3, 3-diphenylpyrrolidine (33.7 mg/day/1000 people). The pooled level rate was 190.16 mg/day/1000 people for benzoylecgonine (main urinary cocaine metabolite), 137.9 mg/day/1000 people for 11-nor-9-carboxy-delta9-tetrahydrocannabinol (main metabolite of cannabis), and 33.7 mg/day/1000 people for 2-ethylidene-1,5-dimethyl-3, 3-diphenylpyrrolidine (main metabolite of methadone). The I2 values for all selected drugs were 100% (P value < 0.001). The results of year subgroup indicated that the changes of heterogeneity for all selected drugs were nearly negligible. The heterogeneity within studies based on continents subgroup just decreased in America for drugs like 11-nor-9-carboxy-delta9-tetrahydrocannabinol (I2 = 24.4%) and benzoylecgonine (I2 = 94.1%). The outcome of this meta-analysis can be used for finding the illicit drugs with global serious problem in view of consumption rate (i.e., cannabis and cocaine) and helping authorities to combat them.

Fabrication of novel 2D Ag-TiO2/γ-Al2O3/Chitosan nano-composite photocatalyst toward enhanced photocatalytic reduction of nitrate.

The presence of excess nitrate in groundwater limits it use as a drinking water supply and its removal is critical to balance the nitrogen cycle in aquatic systems. In this study, ultra-thin 2-dimensional Ag-TiO2/γ-Al2O3/Chitosan (Ag-TiO2/Al2O3/CS) nano-composite was synthesized for the fast reduction of nitrate under UVA irradiation from aqueous solutions. As-synthesized nano-composite was well characterized by X-ray diffraction, transmission electron microscopy, N2 adsorption-desorption isotherms, Fourier-transform infrared spectroscopy and UV-vis diffuse reflectance spectroscopy. Experimental variables including pH, nitrate concentration, photocatalyst dose and contact time were considered to demonstrate their effect on the rate of nitrate reduction. Formic acid was used as a radical scavenger at optimal concentration of 2:1 (formic acid:nitrate). The results showed that upon UVA irradiation, the synthesized nano-composite exhibited fast nitrate reduction in broad pH range (about 74% removal at pH 11 in 5 min reaction time) in diverse water chemical conditions. The Ag-doped and hybrid heterostructures can effectively utilize UV-visible-light to remove nitrate and degrade formic acid. For the 3 cycles the photocatalyst efficiency remained same and after the third cycle, its efficacy decreased gradually. This work suggests 2D Ag-TiO2/Al2O3/CS nano-composite for the fast removal of nitrate in drinking water treatment.

One-Pot Synthesized Visible Light-Driven BiOCl/AgCl/BiVO4 n-p Heterojunction for Photocatalytic Degradation of Pharmaceutical Pollutants.

A novel enhanced visible light absorption BiOCl/AgCl/BiVO4 heterojunction of photocatalysts could be obtained through a one-pot hydrothermal method used with two different pH solutions. There was a relationship between synthesis pH and the ratio of BiOCl to BiVO4 in XRD planes and their photocatalytic activity. The visible light photocatalytic performances of photocatalysts were evaluated via degradation of diclofenac (DCFF) as a pharmaceutical model pollutant. Furthermore, kinetic studies showed that DCF degradation followed pseudo-first-order kinetics. The photocatalytic degradation rates of BiOCl/AgCl/BiVO4 synthesized at pH = 1.2 and pH = 4 for DCF were 72% and 47%, respectively, showing the higher activity of the photocatalyst which was synthesized at a lower pH value. It was concluded that the excellent photocatalytic activity of BiOCl/AgCl/BiVO4 is due to the enhanced visible light absorption formation of a heterostructure, which increased the lifetime of photo-produced electron-hole pairs by creating a heterojunction. The influence of pH during synthesis on photocatalytic activity in order to create different phases was investigated. This work suggests that the BiOCl/AgCl/BiVO4 p-n heterojunction is more active when the ratio of BiOCl to BiVO4 is smaller, and this could be achieved simply by the pH adjustment. This is a promising method of modifying the photocatalyst for the purpose of pollutant degradation under visible light illumination.

Photo-assisted catalytic degradation of acetaminophen using peroxymonosulfate decomposed by magnetic carbon heterojunction catalyst.

Catalytic oxidative degradation of acetaminophen (ACT) was evaluated using magnetic mesoporous carbon (MNPs@C) coupled with UV light and peroxymonosulfate (PMS). The performance of hybrid system (i.e., MNPs@C/UV/PMS) was assessed as a function of some operational factors (e.g., reaction time and different concentrations of catalyst, PMS and ACT) in a batch system. MNPs@C represented a high magnetic response and was easily recovered from aqueous solution via an external magnet. A significant synergistic effect was observed among the applied techniques in MNPs@C/UV/PMS system for ACT degradation. After 40 min reaction, the removal efficiencies of 97.4 and 63.5% were obtained for ACT and TOC, respectively. Both adsorption and oxidation mechanisms were responsible simultaneously for ACT removal in MNPs@C/UV/PMS system. Under optimum conditions, the removal rates of ACT and TOC were reduced slightly to 91.7 and 49.4% after five consecutive catalyst uses, which indicates the excellent reusing potential of MNPs@C. In addition, a high stability was detected for as-prepared catalyst during recycling tests, since the quantity of leached Fe was <0.2 mg/L. Methanol and tert-butyl alcohol showed a strong quenching effect on the performance of MNPs@C/UV/PMS system, demonstrating the dominant role of SO4•- and HO radicals in ACT degradation process. MNPs@C in comparison with ferrous ions, as a homogeneous catalyst, showed a better performance in the activation of PMS and ACT degradation. Integration of MNPs@C, UV and PMS exhibited an excellent performance into ACT removal over 40 min reaction, which can be utilized as an effective and promising technique for the efficient decontamination of polluted waters.

Chitosan modified N, S-doped TiO2 and N, S-doped ZnO for visible light photocatalytic degradation of tetracycline.

N, S-doped TiO2 (NST), N, S-doped ZnO (NSZ) and their composite with chitosan (NST/CS, NSZ/CS) were synthesized by sol gel-hydrothermal method. The prepared samples were characterized using XRD, FTIR, TEM and BET techniques. These photocatalysts were used for the photocatalytic degradation of tetracycline under visible light irradiation. At screening test, NST/CS had the highest tetracycline degradation efficiency of 91% for duration of 20 min under visible light. The blending of chitosan with NST increases the rate of photocatalytic degradation of tetracycline about 2 times. A detail characterization including HRTEM, SEM, EDS and DRS were conducted for NST/CS, the most active photocatalyst in this study. Photocatalytic activity test was conducted by varying tetracycline concentration, irradiation time, catalyst's concentration and pH using response surface methodology to find out the optimum condition for photocatalytic activity. The reusability of as-synthesized NST/CS was assessed which due to its high recoverability can be applied as an effective catalyst for degradation of organic substances in water and wastewater especially for degradation of emerging pollutants such pharmaceutical pollutants. The results from this work show a promising material for local authorities and pharmaceutical facilities to use for the treatment of pharmaceutical pollutants and tetracycline removal in water resource.

Interactions of Cd, Cr, Pb, Ni, and Hg in their effects on activated sludge bacteria by using two analytical methods.

Since trace metals rarely appear singly in industrial effluents, it is a major challenge to address combined effects of such toxicants on biological units of wastewater treatment plants. The aim of this study was interaction assessment of Cd, Cr, Pb, Ni, and Hg in their effects on activated sludge bacteria using analytical methods. Two mathematical models were used to determine the effect of binary mixtures of Hg, Cd, Cr, Pb, and Ni on activated sludge bacteria using a dehydrogenase enzyme assay. Calculated EC50 values were compared to experimentally observed values of mixtures. Interactive effects were counted to be antagonistic for Hg and Cd, Cd and Pb, Cd and Ni, and Cr and Pb, synergistic for Cd and Cr and Hg and Cr, and additive for other binary mixtures. Maximum toxicity was related to Hg and Cr, Cd and Cr, and Hg and Cd. Physicochemical monitoring of single metals may underestimate hazards arising from these pollutants in environmental samples. Therefore, any possible interaction between metals in such environments should be considered when establishing environmental safety standards.

Efficiency of sequencing batch reactor for removal of organic matter in the effluent of petroleum wastewater.

The main aim of this research was to study the biodegradation of Methyl Tertiary Butyl Ether (MTBE) using aerobic sequencing batch reactor (SBR) at a pilot-Scale. The reactor was made of a 3 mm-thick glass cylinder with an internal diameter of 12 cm and height of 60 cm. SBR operated in five phases. The first phase was filling the reactor for about 10 min. the second phase was the main reactor for biological treatment of petroleum wastewater about 21.55 h. The third phase was the sedimentation (1 h). The fourth phase was decanting from the reactor for about 10 min. The last phase consisted of idle for about 45 min. The experiments showed that the mixed microbial mass is able to degrade high concentration of methanol up to 250 mg/l, and concentration of MTBE up to 70 mg/l for a 24 h cycle. However, the mixed microbial mass is not able to degrade MTBE with concentration more than 70 mg/l. Microorganisms were generally isolated from Fajr petrochemical wastewater treatment plant. Analysis showed that the mixed microbial mass able to biodegradation of COD up to 1350 mg/l in effluent. Aerobic SBR can be used for biological treatment of the petroleum wastewater containing pollutants such as methanol, MTBE with a promising efficiency.

Concentrations of arsenic and lead in rice (Oryza sativa L.) in Iran: A systematic review and carcinogenic risk assessment.

Exposure to heavy metals such as arsenic (As), lead (Pb), and cadmium (Cd) in either the short or the long term can cause cancers in humans. Dietary intake and consumption of rice (Oryza sativa L.) is increasing in Iran, and several studies on the concentration of heavy metals in rice have been carried out in this country in recent years. In this perspective, the main objective of the present study was to investigate, even via a meta-analysis of the existing literature, the presence of As and Pb in rice from many geographical areas in Iran, as well as to estimate the carcinogenic risk of these heavy metals in rice consumers. The results of the present ten years-spanning systematic review indicate that 21 reports, collecting a total of 2088 samples, were performed between 2008 and October 2017. The minimum and maximum concentration of As was observed in the Golestan area (0.01 ±â€¯0.01 mg/kg d.w) and the Gillan region (3 mg/kg d.w); and Pb in the Shahrekord (0.07 ±â€¯0.02 mg/kg d.w) and Mazandaran (35 mg/kg d.w). The meta-analysis of data showed that pooled concentration of As in the rice was 0.04 (95%CI: 0.02-0.06 mg/kg d.w), which resulted lower than the National Standard (NS) limits. However, the pooled concentration of Pb in the rice was 0.38 (95%CI: 0.25-0.5 mg/kg d.w), i.e., higher than NS limits. The heterogeneity was significant between As (I2 = 63%, P value = .003) and Pb (I2 = 96%, P value < .001) studies. The carcinogenic risk assessment showed that minimum and maximum incremental lifetime cancer risk (ILCR) of As was in the 45-54 (4.53 × 10-2) and 15-24 (5.50 × 10-2) year age groups consumers; and Pb, 45-54 (2.442 × 10-3) and 15-24 (2.96 × 10-3), respectively. The overall carcinogenesis risk of As (4.864 × 10-2) was 18.5 times higher than Pb (2.623 × 10-3). All age groups consumers of rice content of As and Pb are at considerable carcinogenesis risk (ILCR > 10-3). Therefore a decreased level of heavy metals in rice cultivation should be encouraged and performed in next planning.

Enhanced sonochemical degradation of tetracycline by sulfate radicals.

Tetracyclines (TCs) are widely used antibiotics in human and veterinary medicine and as growth promoters in the world. Sulfate radical-based advanced oxidation processes have been of great interest due to the high oxidizing potential of sulfate radical to degrade refractory organic pollutants in aqueous solution. In this study, the degradation of antibiotic TC in aqueous solution by silver-activated persulfate (Na2S2O8) in the presence of ultrasound irradiation under various conditions has been investigated. The effects of several parameters such as Ag2SO4, Na2S2O8 concentration, temperature, ultrasonic (US) power, initial TC concentration and initial pH on the degradation of TC were investigated. More than 83% of TC removal was achieved within 120 min under optimal conditions. The optimum operational conditions were found to be as follows: Ag2SO4 dosage 3.5 mmol/L, Na2S2O8 concentration 70 mmol/L, reaction temperature 25 °C, US power 120 W, initial TC concentration 50 mg/L, pH 3.0 and contact time 120 min. The degradation of TC in the persulfate/Ag(+)/US process followed the pseudo-first-order kinetics.

Occurrence of non-steroidal anti-inflammatory drugs in Tehran source water, municipal and hospital wastewaters, and their ecotoxicological risk assessment.

Pharmaceuticals are becoming widely distributed in waters and wastewaters and pose a serious threat to public health. The present study aimed to analyze non-steroidal anti-inflammatory drugs (NSAIDs) in surface waters, drinking water, and wastewater in Tehran, Iran. Thirty-six samples were collected from surface waters, tap water, and influent and effluent of municipal and hospital wastewater treatment plants (WWTP). A solid-phase extraction (SPE) followed by liquid chromatography-tandem mass spectrometry method was used for the determination of pharmaceuticals, namely ibuprofen (IBP), naproxen (NPX), diclofenac (DIC), and indomethacin (IDM). IBP was found in most of the samples and had the highest concentration. The highest concentrations of NSAIDs were found in the municipal WWTP influents and hospital WWTP effluents. In the municipal WWTP influent samples, the concentrations of IBP, NPX, DIC, and IDM were 1.05, 0.43, 0.23, and 0.11 µg/L, respectively. DIC was found only in one river sample. All NSAIDs were detected in tap water samples. However, their concentration was very low and the maximum values for IBP, NPX, DIC, and IDM were 47, 39, 24, and 37 ng/L, respectively, in tap water samples. Results showed that the measured pharmaceuticals were detected in all rivers with low concentrations in nanograms per liter range, except DIC which was found only in one river. Furthermore, this study showed that the aforementioned pharmaceuticals are not completely removed during their passage through WWTPs. A potential environmental risk of selected NSAIDs for the urban wastewater has been discussed. However, given their low measured concentrations, no ecotoxicological effect is suspected to occur.